5886( 11) - 10/16/95 11:40 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 5886 Version: 11 Check-in Date: ********** 1.Proposal Title: An In-depth Study of Transition Region Physics: Capella ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Cool Stars GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Jeffrey Linsky University of Colorado CoI: Brian Wood University of Colorado N CoI: Dr. Tom Ayres University of Colorado N CoI: Dr. Phil Judge High Altitude Observatory N CoI: Dr. Alec Brown University of Colorado N CoI: Dr. G. Harper University of Colorado N ------------------------------------------------------------------------------------ 6. Abstract With the brightest UV emission line spectrum of any late-type star, Capella provides an excellent target for detailed studies of physical processes occuring in magnetically heated plasmas, commonly called transition regions, at temperatures of 10^4 - 10^5 K. In our recently completed analysis of GHRS spectra of Capella (Linsky et al. 1994), we find three distinct transition regions in the Capella system -- the plasma on the hotter star (G1 III) that emits moderately broad lines, the plasma on the cooler star (G8 III) that emits narrow lines, and microflaring plasma on the hotter star that emits very broad lines. We now propose a follow-up study to answer the critical new questions raised in the previous work that require analysis of a very different data set. Our objectives are (1) to determine the relative roles of recombination and collisional excition in the formation of the He II 1640 Angstrom line in both stars, (2) to obtain accurate values of the electron density in both the moderately broad and very broad line regions on the hotter star, (3) to obtain an accurate measurement of the differential emission measure distribution of the microflaring component, and (4) to measure the coronal Fe XXI 1354 Angstrom and Fe XII 1349 Angstrom lines for comparison with models based on x-ray data and to determine their Doppler shift and coronal turbulence. The analysis of the requested data will form a portion of Brian Wood's Ph.D thesis. ------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 2] Observations Description ------------------------ Table 1 describes the estimated count rates (based mostly on our previous GHRS data) and observing times needed to reach S/N=30 per diode. The estimate of the Fe XXI flux comes from the measured value for AU Mic (Maran et al. 1994) since the slightly larger emission measure at 10^7 K for Capella obtained from EUVE data by Dupree et al (1994) is compensated by Capella's slightly larger distance. We require ECH-A spectra of the He II line to resolve the recombination lines from the cooler star and of the C II lines to measure the self-reversal and interstellar features. The G140M spectrum of the 1400 Angstrom region will provide additional spectral resolution compared to G160M at similar sensitivity. With COSTAR we can use the LSA with no significant loss of spectral resolution. The mean line fluxes were obtained by dividing the line flux by the observed FWHM. TABLE 1. ESTIMATED EXPOSURE TIMES Spectral & Line flux & Mean line flux &Grating & Count rate &Time (min) for Feature &(erg/cm2/s)& (erg/cm2/s/A) & &(cts/diode/s)& S/N=30/diode ------------ ------------------------------------------------------------------ C II 1335 & 1.8e-11 & 2.1e-11 & EA & 2.8 & 5.4 Fe XXI 1354& 2.4e- 15 & 6.5e-15 & G160M & 0.0047 & ... O IV] 1400 & 4.3e-13 & 6.8e-13 & G140M & 0.35 & 43 O V 1371 & 3.0e-13 & 4.9e-13 & G160M & 0.34 & 44 N IV] 1486 & 1.1e-12 & 1.8e-12 & G160M & 0.88 & 17 He II 1640 & 7.6e-12 & 1.0e-11 & EA & 0.41 & 36 O III] 1666& 3.7e-12 & 6.3e-12 & G160M & 3.1 & 4.8 Table 2 summarises the actual exposures that fit into a 9 orbit program. We have increased the exposure times for the observations to fill out orbits and get better S/N in the emission lines. Our exposure time for the G160M setting at 1360 Angstroms is comparable to that used to observe the Fe XXI line in AU Mic, but the better spectral resolution with COSTAR will help in separating the Fe XXI line from the nearby C I line. It is difficult to avoid the South Atlantic Anomaly for 9 consecutive orbits, so our observations will be split into 2 visits to improve the schedulability of the proposal. The observations using the side 1 gratings (Ech-A and G140M) of the GHRS will be made during one visit and the observations using the side 2 gratings (G160M) will be made during the other visit. Target acquisition will be performed with the N1 mirror for the side 1 visit and with the A2 mirror for the side 2 visit. Most of our observations will be done with the FP-SPLIT option to optimize S/N. The Ech-A observations will be taken through the small science aperture to optimize the wavelength calibration. The other observations will be made through the large aperture to ensure photometric accuracy. Wavelength calibration images will be made before each observation. TABLE 2. PROPOSED OBSERVATIONS Grating & Central & Exp. Time & Remarks & wavelength & (min) & ----------------------------------------------------------------- ----------- EA & 1335 & 13 & High resolution of the C II lines G160M & 1362 & 154 & O V, Fe XXI, and Fe XII upper limit G140M & 1405 & 71 & For S/N=40 in the O IV] lines G160M & 1480 & 30 & N IV] EA & 1640 & 51 & Highest resolution of the He II feature G160M & 1655 & 18 & O III] lines and lower res. He II Real Time Justification ----------------------- We request observations of Capella at orbital phase Phi=0.75+/- 0.05, where the ephemeris for Phi=0.0 is JH (helio) = 2,442,093.347 + 104d.0204E. Possible observing dates (can be +/- 5 days) are: 1994 day 308 (Nov 4); 1995 day 47 (Feb 16), day 151 (May 30), day 255 (Sept 12), and day 359(Dec 25): 1996 day 98 (Apr 8), 202 (July 21), 306 (Nov 1). We need to observe near a quadrature to separate in velocity the contributions of each star. Since most of our previous data were obtained near phase 0.25, we should observe near phase 0.75 to verify that we are assigning the lines to the right star. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 3] Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 HD34029 STAR, G III-I RA = 05H 16M 41.35S +/- 0.01S, J2000 V = V = 0.08 +/- 0.01 DEC = 45D 59' 52.9" +/- 0.1" +29.5 B-V = 0.80 +/- 0.01 F-LINE(1335) = 21 +/- 2 E-12 W-LINE(1335) = 0.75 +/- 0.05 F-LINE(1356) = 8 +/- 1 E-12 W-LINE(1356) = 0.42 +/- 0.05 F-LINE(1394) = 15 +/- 1 E-12 W-LINE(1394) = 0.83 +/- 0.02 F-LINE(1486) = 18 +/- 5 E-13 Comments: F-LINE(1640) = 10 +/- 1 E-12, W-LINE(1640) = 0.74 +/- W-LINE(1486) = 0.6 +/- 0.1 0.03 Coordinates, PM from Hipparcos INCA Epoch of Position RA proper motion (seconds of time/yr) DEC Proper Motion (arcsec/yr) Annual Parallax (arcsec) 2000.000 0.0073 -0.425 0.075 5886( 11) - 10/16/95 11:40 - [ 5] Visit: 01 Visit Requirements: PERIOD 104.0204D AND ZERO-PHASE JD2442093.347 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD34029 HRS ACQ 2.0 MIRROR-N1 1 13.5S ONBOARD ACQ FOR 2-4; PHASE 0.70 TO 0.80 Comments: STEP-TIME = 1.5 sec ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1405 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 3 HD34029 HRS ACCUM 2.0 G140M 1405 FP-SPLIT=STD, 3 1414.4S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 HD34029 HRS ACQ/PEA 0.25 MIRROR-N1 1 37.5S ONBOARD ACQ FOR 5-8 KUP Comments: STEP-TIME = 1.5 sec ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 ECH-A 1335 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 HD34029 HRS ACCUM 0.25 ECH-A 1335 FP-SPLIT=STD, 1 761.6S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE HRS ACCUM SC2 ECH-A 1640 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 8 HD34029 HRS ACCUM 0.25 ECH-A 1640 FP-SPLIT=STD, 2 1740.8S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 6] Visit: 02 Visit Requirements: PERIOD 104.0204D AND ZERO-PHASE JD2442093.347 On Hold Comments: Additional Comments: SAA avoidance requires that we use 2 visits. We would prefer that the visits be in the same visibility period. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 9 HD34029 HRS ACQ 2.0 MIRROR-A2 1 1.8S ONBOARD ACQ FOR 10-15; PHASE 0.70 TO 0.80 Comments: STEP-TIME = 0.2 sec ------------------------------------------------------------------------------------------------------------------------------------ 10 WAVE HRS ACCUM SC2 G160M 1480 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 11 HD34029 HRS ACCUM 2.0 G160M 1480 SPYBAL=NO 6 299.2S ------------------------------------------------------------------------------------------------------------------------------------ 12 WAVE HRS ACCUM SC2 G160M 1655 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 13 HD34029 HRS ACCUM 2.0 G160M 1655 FP-SPLIT=STD, 1 1088S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 14 WAVE HRS ACCUM SC2 G160M 1362 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 15 HD34029 HRS ACCUM 2.0 G160M 1362 FP-SPLIT=STD, 5 1958.4S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 7] Visit: 03 Visit Requirements: PERIOD 104.0204D AND ZERO-PHASE JD2442093.347 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 HD34029 HRS ACQ 2.0 MIRROR-N1 1 13.5S ONBOARD ACQ FOR 2-4; PHASE 0.70 TO 0.80 Comments: STEP-TIME = 1.5 sec ------------------------------------------------------------------------------------------------------------------------------------ 2 WAVE HRS ACCUM SC2 G140M 1405 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 3 HD34029 HRS ACCUM 2.0 G140M 1405 FP-SPLIT=STD, 3 1414.4S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 4 HD34029 HRS ACQ/PEA 0.25 MIRROR-N1 1 37.5S ONBOARD ACQ FOR 5-8 KUP Comments: STEP-TIME = 1.5 sec ------------------------------------------------------------------------------------------------------------------------------------ 5 WAVE HRS ACCUM SC2 ECH-A 1335 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 6 HD34029 HRS ACCUM 0.25 ECH-A 1335 FP-SPLIT=STD, 1 761.6S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 7 WAVE HRS ACCUM SC2 ECH-A 1640 1 DEF ------------------------------------------------------------------------------------------------------------------------------------ 8 HD34029 HRS ACCUM 0.25 ECH-A 1640 FP-SPLIT=STD, 2 1740.8S SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ 5886( 11) - 10/16/95 11:40 - [ 8] Summary Form for Proposal 5886 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations HRS ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACCUM ACQ/PEAKUP ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters FP-SPLIT=STD SPYBAL=NO ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Cool Stars ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements PERIOD 104.0204D AND ZERO-PHASE JD2442093.347 ONBOARD ACQ FOR 2-4; PHASE 0.70 TO 0.80 ONBOARD ACQ FOR 5-8 ONBOARD ACQ FOR 10-15; PHASE 0.70 TO 0.80 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR-N1 G140M ECH-A MIRROR-A2 G160M ------------------------------------------------------------------------------------------------------------------------------------ Target Names HD34029 WAVE ------------------------------------------------------------------------------------------------------------------------------------